Instruction manual

MODEL XMT-C SECTION 8.0

CALIBRATION — CONDUCTIVITY

8.3 CALIBRATING THE SENSOR IN A CONDUCTIVITY STANDARD

This procedure is used to check and correct the conductivity reading of the Model Xmt-C to ensure that the read-

ing is accurate. This is done by submerging the probe in the sample of known conductivity, then adjusting the dis-

played value, if necessary, to correspond to the conductivity value of the sample.

This procedure must always be done after cleaning the probe. The temperature reading must also be checked and

standardized if necessary, prior to performing this procedure.

Important: If you are submerging the probe in the commercial conductivity standard solution, follow steps 1

through 3 below. If you are leaving the probe submerged in a chemical solution bath and checking conduc-

tivity against a laboratory instrument, complete the meter cal procedure in Section 8.4.

1. Be sure that the probe has been cleaned of heavy deposits of dirt, oils, or chemical residue.

2. Commercial standards are referenced to a known temperature, for example, 4000 micromhos at 25°C (77°F).

As the temperature of the standard changes, the conductivity will change. Therefore it is recommended that

this procedure be performed at a temperature between 22 and 28 °C. Be sure the probe has reached a sta-

ble temperature before standardizing.

3. Pour the standard into a clean container. Submerge the clean probe in the standard. Place the probe so that

a minimum of 1 in. of liquid surrounds the probe. Do not allow the probe to be closer than 1 in. to the sides

or bottom of the container. Shake the probe slightly to eliminate any trapped air bubbles. Observe the dis-

played conductivity to determine if the sensor needs to be moved.

Alternatively, the probe can be calibrated while inserted in the process. This is done by adjusting the Model Xmt-C

conductivity reading to the known conductivity of the process water which is close to the probe to be calibrated.

a. Choose In Process. Press ENTER. The screen at the left will appear.

b. Using the arrow keys, enter the actual conductivity of the conductivity

standard in μS/cm. Press ENTER. The screens at the left will appear

during this standardization process.

The conductivity reading in the display will change to the new value and

the cell constant or cell factor will be recalculated. The cell factor can be

viewed in the information screens.

If too large an adjustment is attempted, the transmitter will display

"calibration error" and no change will be made.

Updated Cell

Const: 1.0013/cm

Cal in progress.

Please wait.

Live 10.00μS/cm

Cal

0.00μS/cm